This application claims the priority of Korean Patent Application No. 2003-48664 filed on Jul. 16, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a compound derivative, in which an electron acceptor and an electron donor are coupled, and more particularly, to a compound derivative of carbamate, a method of synthesizing the same, and a molecular device using the same.
2. Description of the Related Art
A molecular electronic or a molecular optical device that has been currently reported is mainly in the form of an electronic device, has a basic structure of two metal electrodes and an organic molecular layer disposed between two metal electrodes. The organic molecule is configured to have a characteristic of organic semiconductor between the molecule two metal electrodes. In this case, the dimension of the organic molecule is in a range of a few nano meters.
Generally, the structure of the molecular device is determined from the disposition method of the organic molecule between the two electrodes, however, the structure can broadly be divided into two structures, i.e., a horizontal and a vertical structure. The horizontal structure has a configuration that an organic compound is disposed between the two metal electrodes placed on a same plane. That is, after forming a gap having nano distance between the two electrodes according to an existing semiconductor manufacturing process, the organic compound is disposed in the gap. While, the vertical structure is formed that a lower electrode is first formed, and an organic compound is placed on the lower electrode, and then an upper electrode is placed on the organic compound.
Until the present time, the organic molecular device material required for the development of the molecular electronic device has been sought out, focusing mainly on the functional purposes, such as a characteristic of molecular wire, a molecular switch, and a molecular rectifier. These technical fields have been studied mostly in advanced countries including U.S.A and Europe as the development of nano technology.
The development history of the molecular rectifying device has the same chronicle as the development of the molecular electronic device. The necessity of development of a molecular device was first proposed through a desire to develop a device utilizing the diode characteristic, i.e., an organic semiconductor characteristic of a molecular rectifying material. Aviram and Ratner of IBM in 1974 introduced a method of formation of a device having a molecular diode rectifying characteristic using a unit molecular characteristic.
According to Aviram and Ratner, when an electron donor (D) and an electron acceptor (A) in a molecule exist in the form of a sigma bond which acts as a spacer, a polarization will occur in the molecule with one directional polarization. After the polarized molecules are arranged in one direction, that is, when forming an electron donor-spacer-electron acceptor structure, a metal electrode on each side is connected, and current will flow in one direction.
This hypothesis was proven by Mattern and his co-workers in 1999 through a partial experiment. They reported that a rectifying characteristic was realized from the experiment carried out by forming an organic LB (Langmuir film) between two electrodes. Also, Metzger group found that the rectifying characteristic can be realized in π-bond instead of σ-bond. Professor M. A. Reed et al. in Yale University have reported that a rectifying diode characteristic can be generated by using an electric potential difference between two metals, such as gold and titanium, in an asymmetric organic compound which has no electron donor-spacer-electron acceptor.
Despite of efforts to develop a rectifying diode device using an organic molecular characteristic, a clear and direct proof regarding the rectifying characteristic of the molecular electronic device, as to whether it is generated from the organic molecular characteristic has not been disclosed yet. Up to the present time, the question of the rectifying characteristic of the molecular device using an organic molecule can not be explained whether it comes from the sole characteristic of the organic compound or it is a phenomenon occurred between the two metals including the organic molecule.
Accordingly, there is a strong desire to develop a new molecular rectifying material that can explicate the rectifying characteristic of molecular electronic device. However, the development of a molecular rectifying material is very difficult. Particularly, a synthetic difficultness of an organic compound is considered as a big hindrance for developing a molecular rectifying material.
For example, when an electron donor and an electron acceptor are co-existed in a reactor, a precipitation, generally in the form of a salt, will occur due to a charge transfer between the two molecules. For this reason, synthesizing a covalent compound having an electron donor-sigma bond-electron acceptor required for forming the molecular electron rectifying material is practically difficult.